1. Field
One or more embodiments of the present invention relate to a nucleic acid aptamer commonly and selectively binding to various types of microorganisms, and a method of manufacturing the same.
2. Description of the Related Art
An aptamer is generally referred to a single-stranded DNA or RNA having high specificity and affinity for a specific target material. Aptamers have advantages over antibodies in that aptamers have higher affinity for a target material than that of antibodies that are mainly used in the field of sensors for disease diagnostic technology, biosensor, or detection for harmful microorganism, and long-term storage of aptamers at room temperature is possible due to excellent thermal stability thereof. In addition, easy chemical synthesis of aptamers enables low cost and large scale production of aptamers with high purity without need to obtain antibodies by injecting antigens into animals. Therefore, many studies have been made on the development of aptamers having high specificity and affinity for a specific target material to take advantages in diagnostic and therapeutic techniques or in use of biosensors.
Systematic evolution of ligands by exponential enrichment (SELEX) techniques regarding aptamer selection are protected by essential patent of Gold and Tuerk disclosing “Methods for identifying nucleic acid ligands (refer to U.S. Pat. No. 5,270,163)”, but the patent expired on Dec. 14, 2010. Accordingly, techniques regarding aptamer screen that are relatively less active until now become more active, and accordingly, a variety of modified SELEX methods are developed. For example, Cell SELEX refers to a method of selecting aptamers that have the highest binding force to a surface of whole cells, unlike conventional SELEX techniques that are used with respect to purified proteins or chemicals. Cell SELEX may be used in the case of attempting to recognize specific disease cells but failing to identify proteins associated with disease cells. Many studies on Cell SELEX have been made in terms of mainly recognizing and binding to a surface of specific cancer cells, and recently, studies on Whole Cell SELEX are reported with respect to microorganisms such as Staphylococcus aureus and Escherichia coli, respectively.
However, regarding the aptamer selection method using existing Cell SELEX, aptamers having high selectivity for only one kind of a target material are selected. In detail, the aptamer selection method includes (1) screening only nucleic acids capable of binding to one target material after mixing the target material, such as a specific target microorganism or protein, with a nucleic acid library consisting of random sequences; (2) removing nucleic acid structures that are not bound to the target material and obtaining the nucleic acids capable of binding to the target material; and (3) amplifying the nucleic acids for the next round's selection procedure. These steps (1) to (3) are repeated several to tens of times, thereby discovering nucleic acid aptamers having significantly high affinity and specificity for target materials. That is, the existing Cell SELEX has to limit the subject to one type of a target material without any other choices. However, types of microorganisms vary in rivers, foods, and environmental facilities, and in this regard, no invention has been reported yet relating to development of a universal DNA aptamer for recognizing, detecting, or diagnosing these various types of microorganisms and a method of manufacturing the universal DNA aptamer.